FLOW-INJECTION ELISA FOR PROCESS MONITORING AND CONTROL

A fully automated immunoassay is described. By combining flow-injection analysis with enzyme-linked immunosorbent assay (ELISA), a convenient and rapid flow-ELISA system was established. The assay principle is based on the competitive binding between an antibody and a native antigen in the sample and an enzyme-labelled antigen added in a fixed amount. The antibodies are immobilized to a solid support and placed in a small column in the flow system. After one assay cycle, the system is rinsed and the column is reused for the next assay. The total time for one assay cycle is 6-10 min, depending on the conditions. In this model study protein A-IgG interactions were used instead of real immunochemical interaction. The whole procedure is controlled by a personal computer, with sampling, addition of labelled antigen, washing, monitoring, evaluation, dissociation and reconditioning being computer controlled. The program is designed to compensate for denaturation of antibodies on the column. The flow-ELISA in its present form has been shown to be suitable for on-line monitoring of biological macromolecules.